DC shunt motor work on no load ?why?
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In series motor field winding is in series to armature winding. In any DC motor the speed depends inversely on the flux and directly proportional to emf, N ~E/flux.
Motor armature current is decided by the load.On no load the armature current drawn by the motor will very small.
For d.c. series motor,
Flux is Directly proportional to Armature current.
and on no load as Ia is small hence flux produced is also very small.
According to speed equation,
Speed is Inversely proportional to Flux i.e ( N α 1/Φ)
as Eb is almost constant.
As from Speed Equation Speed is inversely proportional to flux and for no load or less load the flux produced is also less hence the rotor rotates at very high speed which can damage the motor mechanically.
This is the reason why series motor should never be started on light loads or no load conditions.
Motor armature current is decided by the load.On no load the armature current drawn by the motor will very small.
For d.c. series motor,
Flux is Directly proportional to Armature current.
and on no load as Ia is small hence flux produced is also very small.
According to speed equation,
Speed is Inversely proportional to Flux i.e ( N α 1/Φ)
as Eb is almost constant.
As from Speed Equation Speed is inversely proportional to flux and for no load or less load the flux produced is also less hence the rotor rotates at very high speed which can damage the motor mechanically.
This is the reason why series motor should never be started on light loads or no load conditions.
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